PH reduced but TA did not

[prasadkm0204]

My TA was at 160ppm and PH at 7.8 (slightly above 7.8).
I added 32 oz Muriatic acid and checked in the morning after running pump overnight.

PH has reduced to 7.6 or 7.7 but TA is still 160ppm.

I performed the tests twice and I also use speedstir.
I tried with TF-100 and 2006 test kit. Same result. My drop size is good and I hold the bottle upside down completely (was doing this incorrectly in the initial days where it was slightly slanted)

Am I missing something.

-Prasad

 

[ping]

With that addition of acid the TA will only be lowered by a few points and you will not see that amount show any difference on the TA test.

Use PoolMath and go to effects of adding chemicals section at the bottom of the page, insert all of your pool chem levels before using.

 

[prasadkm0204]

Thanks @ping.
The poolmath does not give numbers for reducing TA. It just says to reduce PH and then aerate.
Since I have a automatic pool cover I did not want to reduce it way down to 7.2

I guess I will approach this gradually. Maybe open up the cover over weekends.

-Prasad

 

[ping]

See this link on the process to reduce the TA, http://www.troublefreepool.com/content/129-how-to-lower-lowering-total-alkalinity.

 

[epro05]

Actually PoolMath does give numbers for reducing TA. If you go to the "Effects of adding chemicals" at the bottom, enter an amount of Muriatic Acid added, it will calculate pH reduction and TA reduction for you.

 

[jblizzle]

Please add your pool volume to your signature ... makes it easier to help you.

If I guess at a volume of 24k, then 32 oz of acid would only lower the TA by about 5ppm ... within the accuracy of the test.

You need to follow the Lower Total Alkalinity process.

 

[prasadkm0204]

Thanks everyone. Looks like I need to add about 300oz to reduce TA by 40 (160-->120) for 30k gal water.
But this will lower PH drastically. So I will have to do it over a few weeks/months.

 

[woodyp]

Yep......it's a process. You can lower PH to 7.4 though.